The central goal of the proposed research is to contribute towards a better understanding of human mental capacities through a detailed study of language. Our research attempts to characterize as precisely as possible the knowledge that must be available to an organism that has fluent command of a language (grammar) and to specify the cognitive faculties with which an organism must be endowed if it is to use this knowledge in all the ways in which humans use language and accomplish the task of acquiring this knowledge in the time and under the highly irregular conditions that language is normally acquired by children. The research centers on the development of linguistic theory viewed as the abstract characterization of the human faculty of language. Since the main testing grounds of scientific theories are their detailed empirical consequences, much of our research is concentrated on the study of narrowly defined topics in the syntax, morphology, semantics and phonology of particular languages; on experiments in psycholinguistics, on inquiries into language acquisition, etc. These technical concerns are usefully supplemented by studies into broader aspects of language and language use; e.g., studies in the special use of language in literature and investigations into the educational potential of linguistics in minority communities that are seeking to define the role that their own language should play in the schooling of their children.